Sliding-gate closure for bottom-pour vessel

ABSTRACT

A sliding gate closure member for a bottom-pour hot metal vessel. The gate includes an erosion-resistant nozzle orifice insert positioned in a low-cost refractory and a hard refractory top plate that presents a crack-free surface to the molten metal, thus preventing the formation of fins. An alternative gate construction has a recessed erosion-resistant nozzle orifice insert positioned in a hard refractory that serves as both a back-up material for the orifice insert and as the top surface of the gate, yet provides similar protection against the formation of fins.

United States Patent Shapland [54] SLIDING-GATE CLOSURE FOR BOTTOM-POUR VESSEL [72] Inventor: James T. Shapland, Wilkins Township, Allegheny County, Pa.

[73] Assignee: United States Steel Corporation [22] Filed: May 1, 1970 [21] Appl. No.: 33,547

[15] 3,685,707 [4 1 Aug. 22, 1972 3,567,082 2/1968 Tinnes ...222/D1G. 7

Primary Examiner-Robert B. Reeves Assistant Examiner-David A. Scherbel Attorney-Ralph H. Dougherty [57] ABSTRACT A sliding gate closure member for a bottoin-pour hot metal vessel. The gate includes an erosion-resistant nozzle orifice insert positioned in a low-cost refractory [52] US. Cl. ..222/559 and a hard refractory top plate that presents a crack hilt. f Surface to molten metal thus preventing he [58] Field 0 Search ..222/DlG. 7, 559, 561 formation of firm An alternative gate construction has 56 R f ed a recessed erosion-resistant nozzle orifice insert posi- 1 e erences n tioned in'a hard refractory that serves as both a backlT STATES PATENTS up material for the orifice insert and as the top surface a of the gate, yet'provides similar protection against the 3,511,261 5/1970 Bick et a1 ..222/DIG. 7 formation ffi 1 3,454,201 7/1969 'Fichera.... ..2 22/DlG. 7

506,328 10/ 1893 Morris ..222/DIG. 7 2 Clains, 7 Drawing Figures 3 4 i 3 2 I I I y g I I {A L PATENTEmuazzmz 3685,70?

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JAMES T. SHAPLAND Attorney PATENTED AUG 2 2 I972 SHEET 2 0F 2 FIG. 3.

Ill ll FIG. 4. 26

, INVENTOR.

. JAMES T. SHAPLAND A! rorney SLIDING-GATE CLOSURE FOR BOTTOM-POUR VESSEL This invention relates to an improved slidable-gate colnstruction for use as a closure on a bottom-pour vesse Although my invention is not thus limited, my gate construction is particularly useful as applied to vessels for pouring molten metal, for example a ladle or tundish. Such vessels have an outlet in the bottom wall through which molten metal is poured into a receiving vessel. It is known to equip the pouring vessel with a slidable gate mounted on the underside of the bottom wall for controlling flow of metal through the outlet, one example of which is shown in my U.S. Pat. No. 3,352,465. The vessel carries a hydraulic operating mechanism for positioning the gate. One practice is to use a reciprocable gate which has both a blank area and a nozzle, as shown in FIGS. 1 to 3 of the patent. The gate is slidable back and forth between positions in which the'blank area underlies the outlet to close it, or the nozzle is aligned with the outlet to permit pouring. Another and usually preferred practice is to use gates of the slide-through type, each of which is either a blank or provides a nozzle, as shown in FIGS. 4 and 5 of the patent. As the operating mechanism shoves each gate into alignment with the outlet, the new gate shoves the preceding gate on past and eventually off the vessel.

Individual gates made of a single piece of refractory as shown in FIG. 6 of the patent, when made from a sufficie ntly erosion-resistant material to have a long useful life, are extremely high cost items. This has led to the practice of making gates from two different types of refractory material. An expensive erosion-resistant refractory is used for the nozzle orifice, and an inexpensive refractory is used as the back-up material surrounding the nozzle. This two-refractory gate has the disadvantage of presenting a crack-containing surface to the molten metal in the ladle nozzle. When the gate is positioned beneath the ladle nozzle, the molten metal oftenfills the crack, forming a fin which will tend to force the gate downward away from the vessel outlet and allow molten metal to flow around the gate.

It is the primary object of my invention to provide an improved gate, applicable to either the reciprocating type or the slide-through type, which is capable of presenting a smooth, crack-free surface to the molten metal in the nozzle of a hot metal vessel, yet has a long useful life, and is available at a low cost.

In the drawings:

FIG. 1 is a vertical-sectional view of portions of a bottom-pour vessel showing the preferred embodiment gate, construction using only two refractories. FIG. 7 is a vertical cross-section taken along line VIIVII of FIG. 6.

FIG. 1 shows a portion of a conventional bottompour vessel 10, which has a metal shell 12 and a refractory lining 13 for containing molten metal. The bottom wall of the bottom-pour vessel has an outlet opening 14 and carries an orifice plate 15 and refractory discharge nozzle 16 fixed to its underside aligned with the opening. A sliding gate closure member 17 is mounted beneath the orifice plate. The gate can be supported and operated in any desired manner; hence I have not shown the supporting and operating mechanism. In accordance with my invention, as best shown in FIG. 5, each gate comprises a low-cost main refractory block 20 of a material such as fire clay, an erosion-resistant refractory nozzle 21, such as zirconia, having a vertical orifice 22, and a refractory top plate 24 having a hole 25, the top of which plate 24 has a smooth surface; The top plate must have the necessary strength and hardmess to withstand the effects of sliding. High alumina refractory is suitable for this application. The refractory gate can be inserted into a metal frame 26, if desired. Mortar 28 can be used between pieces to bond them together.

In the case of a reciprocable gate, shown in FIGS. 3 and 4, a connecting member 30 is attached to the end of the gate.

The invented gate readily performs the function of controlling or stopping the flow of molten metal. However, as the sliding surface of the refractory top plate is a solid piece, there is an absence of cracks'and joints in which metal fins form. Thus I am able to utilize a special erosion-resistant refractory for my nozzle orifice without its attendant difficulties.

I have invented an alternative gate which accomplishes the same objectives as the gate described above. Referring now to FIGS. 6 and 7, the gate depicted therein comprises a main refractory block 32 and a recessed erosion-resistant refractory nozzle 33 inserted therein. Nozzle 33 is positioned in an orifice 34. This gate can also be inserted into a metal frame 36 if desired, and mortar 37 can be used to bond the pieces together. As the crack between the block 32 and nozzle 33 is a part of the orifice 34 through which hot metal flows, no fin is able to form therein. Since block 32 serves as the top of the gate, it must have a relatively hard and smooth top surface. Thus it must be made of some hard, smooth material, such as a high alumina refractory. It can readily be seen that my alternative gate construction is easily adaptable for use in a reciprocable gate.

From the foregoing, it is apparent that I have invented a slidable-gate construction having a low cost and a long useful life, which gate prevents the formation of fins.

I claim:

1. In the combination of a bottom-pour vessel having 7 an outlet in its bottom wall, an orifice plate fixed to the underside of said vessel and a gate slidable on the bottom of said orifice plate, an improved gate comprising a main refractory block having an orifice, said orifice having an upwardly extending wall, and a nozzle of erosion-resistant refractory positioned within said orifice and recessed below the top of said block leaving the portion of the refractory wall of said orifice exposed above the nozzle, said block having a smooth joint-free upper surface surrounding said orifice to serve as the top of the gate, the joint between the refractories of said block and said nozzle being located within said orifice to avoid formation of fins when metal flows through said nozzle.

2. A gate as defined in claim 1 further comprising a metal frame surrounding said gate. 

1. In the combination of a bottom-pour vessel having an outlet in its bottom wall, an orifice plate fixed to the underside of said vessel and a gate slidable on the bottom of said orifice plate, an improved gate comprising a main refractory block having an orifice, said orifice having an upwardly extending wall, and a nozzle of erosion-resistant refractory positioned within said orifice and recessed below the top of said block leaving the portion of the refractory wall of said orifice exposed above the nozzle, said block having a smooth joint-free upper surface surrounding said orifice to serve as the top of the gate, the joint between the refractories of said block and said nozzle being located within said orifice to avoid formation of fins when metal flows through said nozzle.
 2. A gate as defined in claim 1 further comprising a metal frame surrounding said gate. 